1. Field of the Invention
The present invention relates in general to Global Positioning System (GPS) mobile terminals, and in particular to methods and apparatuses for determining the mode of operation of a GPS receiver in a mobile terminal or device.
2. Description of the Related Art
Cellular telephony, including Personal Communication System (PCS) devices and other mobile terminals or devices, has become commonplace. The use of such devices to provide voice, data, and other services, such as internet access, has provided many conveniences to cellular system users. Further, other wireless communications systems, such as two-way paging, trunked radio, Specialized Mobile Radio (SMR) that is used by police, fire, and paramedic departments, have also become essential for mobile communications.
A current thrust in the cellular and PCS arena is the integration of Global Positioning System (GPS) technology into cellular telephone devices and other wireless transceivers. For example, U.S. Pat. No. 5,874,914, issued to Krasner, which is incorporated by reference herein, describes a method wherein the basestation (also known as the Mobile Telephone Switching Office MTSO)) transmits GPS satellite information, including Doppler information, to a remote unit using a cellular data link, and computing pseudoranges to the in-view satellites without receiving or using satellite ephemeris information.
This current interest in integrating GPS with cellular telephony sterns from a new Federal Communications Commission (FCC requirement that cellular telephones be locatable within 50 feet once an emergency call, such as a xe2x80x9c911xe2x80x9d call (also referred to as xe2x80x9cEnhanced 911xe2x80x9d or xe2x80x9cE911xe2x80x9d) is placed by a given cellular telephone. Such position data assists police, paramedics, and other law enforcement and public service personnel, as well as other agencies that may need or have legal rights to determine the cellular telephone""s position. Further, GPS data that is supplied to the mobile telephone can be used by the mobile telephone user for directions, latitude and longitude positions (locations or positions) of other locations or other mobile telephones that the cellular user is trying to locate, determination of relative location of the cellular user to other landmarks, directions for the cellular user via internet maps or other GPS mapping techniques, etc. Such data can be of use for other than E911 calls, and would be very useful for cellular and PCS subscribers.
However, cellular telephones are typically used in environments that are typically not suitable for GPS signal reception, e.g., indoors, in urban environments, or in tunnels or elevators. As such, there are many situations where a cell phone that has an integrated GPS receiver cannot receive GPS signals, because the cell phone is blocked from receiving such signals. Urban canyons, heavy foliage, or other scattering or blocking structures will prevent the receiver from getting the information it needs to determine the location of the cell phone. The cellular system can then be used to deliver information to the GPS receiver for the GPS receiver to perform the necessary calculations.
It can be seen that there is a need in the art for GPS enabled cellular telephones. It can also be seen that there is a need in the art for decision making intelligence accessible to the GPS receiver for determining whether the GPS receiver requires additional information in order to make a position determination.
To minimize the limitations in the prior art described above, and to minimize other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a system for determining the position of a GPS terminal.
In summary, the present invention discloses a system for determining the position of a GPS terminal. The system comprises a GPS terminal, a location aiding server, and a communications system The GPS terminal includes a GPS section for receiving and processing a GPS signal, and a call processing section, where a first message is passed from the call processing section to the GPS section via an interface between the GPS section and the call processing section, and a second message is also passed via the interface from the GPS section to the call processing section in response thereto. The first message comprises a Quality of Service (QoS) message and the second message comprises a QoS response message.
An object of the present invention is to provide for GPS enabled cellular telephones. Another object of the present invention is to provide a system that provides decision making intelligence accessible to the GPS receiver for determining whether the GPS receiver requires additional information in order to make a position determination.